Generalize HeapObject alignment requirements.

Generalize HeapObject alignment requirements.
Removes EnsureDouble* methods.
Adds a RequiredAlignment method.
Changes call sites.

LOG=N
BUG=v8:4124
Committed: https://crrev.com/ebee0aa21a3137d107676a01c39f6399ffd3b732
Cr-Commit-Position: refs/heads/master@{#28541}

[bbudge, 2015-05-21 09:33:21]

Patchset #2 (id:20001) has been deleted

[bbudge, 2015-05-21 09:40:25]

bbudge@chromium.org changed reviewers:
+ bmeurer@chromium.org, hpayer@chromium.org

[bbudge, 2015-05-21 09:40:25]

This is the first part of fixing the GC's handling of alignment. The next CL
will fix the templated scavenging collector functions.

[Hannes Payer (out of office), 2015-05-21 09:53:32]

LGTM, two nits

https://codereview.chromium.org/1150953002/diff/40001/src/objects-debug.cc
File src/objects-debug.cc (right):

https://codereview.chromium.org/1150953002/diff/40001/src/objects-debug.cc#ne...
src/objects-debug.cc:50: // TODO(yangguo): Use this check once crbug/436911 has
been fixed.
That should be fixed now, we can remove the uncommented code.

https://codereview.chromium.org/1150953002/diff/40001/src/snapshot/serialize.cc
File src/snapshot/serialize.cc (right):

https://codereview.chromium.org/1150953002/diff/40001/src/snapshot/serialize....
src/snapshot/serialize.cc:1732: // TODO(bbudge) Generalize to other alignment
constraints.
TODO(bbudge): ...

[bbudge, 2015-05-21 10:02:08]

https://codereview.chromium.org/1150953002/diff/40001/src/objects-debug.cc
File src/objects-debug.cc (right):

https://codereview.chromium.org/1150953002/diff/40001/src/objects-debug.cc#ne...
src/objects-debug.cc:50: // TODO(yangguo): Use this check once crbug/436911 has
been fixed.
On 2015/05/21 09:53:31, Hannes Payer wrote:
> That should be fixed now, we can remove the uncommented code.

Great, Done.

https://codereview.chromium.org/1150953002/diff/40001/src/snapshot/serialize.cc
File src/snapshot/serialize.cc (right):

https://codereview.chromium.org/1150953002/diff/40001/src/snapshot/serialize....
src/snapshot/serialize.cc:1732: // TODO(bbudge) Generalize to other alignment
constraints.
On 2015/05/21 09:53:31, Hannes Payer wrote:
> TODO(bbudge): ...

Done.

[bbudge, 2015-05-21 10:35:28]

The CQ bit was checked by bbudge@chromium.org

[bbudge, 2015-05-21 10:35:28]

The patchset sent to the CQ was uploaded after l-g-t-m from hpayer@chromium.org
Link to the patchset: https://codereview.chromium.org/1150953002/#ps60001
(title: "Review comments.")

[commit-bot: I haz the power, 2015-05-21 10:35:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1150953002/60001

[commit-bot: I haz the power, 2015-05-21 11:06:43]

Committed patchset #3 (id:60001)

[commit-bot: I haz the power, 2015-05-21 11:06:56]

Patchset 3 (id:??) landed as
https://crrev.com/ebee0aa21a3137d107676a01c39f6399ffd3b732
Cr-Commit-Position: refs/heads/master@{#28541}